Pneumatic core shaft



Sept. 17, 1963 G. w. KARR PNEUMATIC CORE SHAFT 2 SheetsSheet 1 Filed Feb. 27, 1961 IN V EN TOR.

lllll lH Gena/a If Mfr Sept. 17, 1963 G. w. KARR PNEUMATIC CORE SHAFT Filed Feb. 27 1961 2 Sheets-Sheet 2 IN VEN TOR. Qeia/a 1 14 1 417" llllll ll lillllll- H n mm M United States Patent Filed Feb. 27, 1961, Ser. No. 91,896 2 Claims. (Cl. 242-72) The present invention relates to improvements in expandible and contractible shafts and particularly to shaft assemblies for supporting and gripping the internal surface of a hollow core such as used in winding and unwinding rolls of paper.

In winding and unwinding rolls of sheet material such as paper, individual small rolls may be wound from a large parent roll with the material of the parent roll often being slit into narrower sheets. The paper is wound on hollow tubular cores from rolls on hollow cores both of which are rotated at relatively high speed and which are supported by central shaft assemblies that are expanded against the inner surface for concentrically supporting the rolls. The shaft assemblies are frequently driven in rotation or brake-d through the shaft or by external contact with the roll to control the speed of rotation of the rolls as is known in winding and unwinding operations, and the shaft assemblies must provide good reliable driving supports in view of the weights of the rolls and the forces which must be applied thereto.

An object of the invention is to provide an improved pneumatically expanded coreshaift assembly of improved construction obtaining more reliable, more effective core support.

A further object of the invention is to provide a core support assembly which employs a full length one-piece center shaft and is of improved construction utilizing a simplified pneumatic tube and an air chamber having a low volume capacity.

A still further object of the invention is to provide an improved core supporting shaft assembly well suited for use in winders, having a simplified improved more rigid construction and providing improved features for changing the tubular elastomeric expansion tube.

A still further object of the invention is to provide a winding core support shaft assembly which does not require removal of portions of a center shaft for replacement of the pneumatic tube, and wherein parts are maintained in firm assembly during rotation preventing out of balance conditions.

A further object of the invention is to provide an improved more rigid more stable core supporting shaft assembly which provides a continuous rigid beam support through the center of the core assembly and which supports a core with reliable accurate concentricity and is capable of supporting substantial weights and sustaining external radial pressures against the core without losing the concentricity.

Other objects and advantages will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiment thereof in the specification, claims and drawings, in which:

FIGURES 1 and 2 are fragmenary elevational views of opposite ends of a core shaft assembly constructed in accordance with the principles of the present invention showing the parts in position for sliding a core on or off the shaft;

FIGURE 3 is a fragmentary elevational view similar to FIGURE -1 but showing the parts in position for gripping a core on the shaft;

FIGURE 4 is a vertical sectional view taken substantially along line IV-IV of FIGURE 1; and

ice

FIGURE 5 is a vertical sectional view taken substantially along line VV of FIGURE 3.

As shown on the drawings:

Extending through the center of the core-supporting shaft assembly shown in the drawings is a continuous one-piece rigid center shaft 10, that acts as a full length beam, having journal ends 11 and 11a for rotatably mounting the shaft, assembly. The ends will usually be releasably held in supporting bearings for removal for slipping a fresh core over the shaft assembly or for the removal of a core therefrom.

Cores are supported on the assembly for rotation therewith by a mechanism which expands radially, shown in the form of an elongated elastomeric tube 12. The shaft extends concentrically through the center of the tube and a small annular air chamber 13 is formed between the tube and shaft. The shaft is slightly reduced at its central portion 14 so as to provide shoulders 15 and 15a which support the ends of the tube. The ends are suitably bonded to the shoulders 15 and 15a such as by annular bindings 16 and 16a that clamp the tube ends radially to the shoulders 15 and 15a. Annular sloping surfaces extend between the shoulders 15 and 15a and the central portion 14. When the tube 12 is 001- lapsed it rests on these sloping surfaces and on the central portion 14.

Supported concentric with the shaft 10 is an outer tubular shell 17. The shell is supported at one end, as shown in FIGURE 1, by an annular collet 18, which may be in arcuate segments or in the form of a split ring, having a tapered outwardly facing annular surface 1 8a which engages the inner surface of the end of the outer shell 17. The collet 18 is supported on the shaft surface 19 and is held axially against the end of the outer shell 17 by a rigid ring 18b and threaded nut 20 turned onto threads 21 on the shaft 1t Thus the coll-et 18 and the ring 18b and nut 20' provide radial and axial support for the outer shell at one end. At the other end, as shown in FIGURE 2, the shell 17 slides lover a tapered surface 19a which supports it radially and the end abuts a radial face 1% which provides axial support. When the nut 20 of FIGURE 1 is tightened, the tube is rigidly clamped in an axial direction between the collet 18 and theradial face 1%. Both ends of the shell 17 are rigidly held in a radial and axial direction by the continuous one-piece shaft 10 which provides a rigid beam for carrying the core and its contents.

For lf-rictionally engaging the inner surface of the core and holding it on the outer shell so that it will rotate therewith and remain in a fixed axial position thereon, individual expander plates 22, 23, 24 and 25 are positioned circumferentially around the tube 12 within the outer shell 17. The expander plates preferably extend the full length of the tube and are substantially the length of the air chamber 13 which is between the tube 12 and the portion 14 of the shaft, FIGURES 3 and 5.

Spaced axially along each of the expander plates 22 are friction buttons, such as shown at 26 for the expander plate 22 and at 27 for the expander plate 24. The friction buttons 26 and 27 extend through openings 28 and 29 through the outer shell 17. These openings are provided for each of the buttons and are positioned at axially and circumferentially spaced locations around the outer shell 17 Thus the expander plates and friction buttons provide friction members operated by the tube to move radially outwardly for engaging the inner surface of the core when the tube is inflated. The expander plates are shown in their expanded position in FIGURES 3 and 5 with the tube 12 inflated in spaces 30 between the plates. The expander plates and tube 12 are shown in their retracted positions when air is permitted to escape from the air chamber 13, in FIGURES 1, 2 and 4. An air inflation passage 31 extends axially from one end through the shaft and opens radially into the air chamber 13. At one end of the shaft 10 is positioned a threaded recess 32 for attaching an air valve for controlling the inflation of the tube 12.

In brief summary of operation, air is exhausted from the air chamber 13 so that the expander plates are retracted radially inwardly as shown by the plates 22 and 24 in FIGURES 1, 2 and 4 and the plates tend to release the buttons simultaneously and also aid in making the pressure uniform between each of the buttons and the core interior surface. A core is slide over the outer shell 17, and when it is axially located, the air chamber 13 is pressurized through the passageway 31. This moves the expander plates radially outwardly, FIGURES 3 and 5, projecting the buttons out through the openings in the shell to held the core in its centered position on the outer shell 17.

Thus it will be seen that I have provided an improved core supporting shaft assembly which meets the objectives and advantages above set forth. The mechanism provides a support with a rigid beam-like continuous shaft center which does not have to be disassembled for attaching the core or for replacing the tube 12. The parts are accurately centered on the shaft 10 for holding the outer shell 17 concentric and for supporting the core and driving a core in rotation at the speed of rotation of the shaft assembly. A small air chamber 13 is provided that requires a minimum of time to inflate and deflate which becomes important on long shafts or large diameter shafts .and inflation pressures can be used in accordance with the frictional contact necessary with a core.

The mechanism is simple in construction and easy to assemble and disassemble and the parts can be reassembled with accuracy after replacement of the expandible tube. All parts are rigidly positioned and supported on the strong center shaft 10.

The drawings and specification present a detailed disclosure of the preferred embodiments of the invention, and it is to be understood that the invention is not limited to the specific forms disclosed, but covers all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

I claim as my invention:

1. A core supporting assembly for winders comprising a continuous one-piece center shaft having journal ends and having a center portion of reduced diameter defining annular shoulders spaced axially inwardly from the ends and outwardly of said center portion, an elastomeric tube coaxially positioned over said center shaft, clamping means holding the ends of the tube against the annular shoulders to form an annular air chamber between the center portion of the shaft and the tube, annular sloping surfaces extending between each of the shoulders and said center portion and coacting with said center portion to form a seat for the tube when it is collapsed radially inwardly,

means defining an inflation passage extending axially from one end of the center shaft and opening into said air chamber, an outer tubular shell concentrically mounted at its ends on the center shaft and having axially and circumferentially spaced radial openings therein, individual expander plates extending axially and located between the tube and outer shell for substantially the length of the air chamber providing circumferential spaces between the plates when forced outwardly against the inner surface of the outer shell, and outwardly projecting friction buttons on each of the expander plates aligned with the openings in the outer shell for frictionally engaging the inner surfaces of a core on the assembly.

2. A core supporting assembly for winders comprising a continuous one-piece center shaft having journal ends and having a center portion of reduced diameter to define annular shoulders spaced axially inwardly from the ends, an elastomeric tube coaxially positioned over said center shaft, clamping means holding the ends of the tube against the annular shoulders to form an annular air chamber between the center shaft and tube, means defining an inflation passage extending axially from one end of the center shaft and opening into said air chamber, an outer rigid metal tubular shell concentrically mounted at its ends on the center shaft and having axially and circumferentially' spaced radial openings therein, an annular collet mounted on the shaft and supporting one end of the outer shell and having a radial shoulder rigidly engaged by the end of the shell, an end nut threaded axially on the center shaft against the collet, means for supporting the other end of the shell having a radial shoulder rigidly engaged by the other end of the shell, individual expander plates extending axially between the tube and outer shell for substantially the length of the air chamber providing axial spaces between the plates when forced outwardly against the inner surface of the outer shell, and outwardly projecting friction buttons on each of the expander plates aligned with the openings in the outer shell for friotionally engaging the inner surfaces of a core on the assembly.

References Cited in the file of this patent UNITED STATES PATENTS 844,461 Newbold Feb. 19, 1907 1,281,861 Sibley Oct. 15, 1918 1,796,534 Pope Mar. 17, 1931 2,215,069 Meisel Sept. 17, 1940 2,289,519 Randall July 14, 1942 2,537,492 Tidland Jan. 9, 1951 2,558,689 Miller June 26, 1951 2,583,117 Piperoux et al Jan. 22, 1952 2,711,863 Grettve June 28, 1955 2,876,961 Cole et al Mar. 10, 1959 OTHER REFERENCES German application 1,042,372, printed Oct. 30, 1958 (KL. 55c 7/05). 

1. A CORE SUPPORTING ASSEMBLY FOR WINDERS COMPRISING A CONTINUOUS ONE-PIECE CENTER SHAFT HAVING JOURNAL ENDS AND HAVING A CENTER PORTION OF REDUCED DIAMETER DEFINING ANNULAR SHOULDERS SPACED AXIALLY INWARDLY FROM THE ENDS AND OUTWARDLY OF SAID CENTER PORTION, AN ELASTOMERIC TUBE COAXIALLY POSITIONED OVER SAID CENTER SHAFT, CLAMPING MEANS HOLDING THE ENDS OF THE TUBE AGAINST THE ANNULAR SHOULDERS TO FORM AN ANNULAR AIR CHAMBER BETWEEN THE CENTER PORTION OF THE SHAFT AND THE TUBE, ANNULAR SLOPING SURFACES EXTENDING BETWEEN EACH OF THE SHOULDERS AND SAID CENTER PORTION AND COACTING WITH SAID CENTER PORTION TO FORM A SEAT FOR THE TUBE WHEN IT IS COLLAPSED RADIALLY INWARDLY, MEANS DEFINING AN INFLATION PASSAGE EXTENDING AXIALLY FROM ONE END OF THE CENTER SHAFT AND OPENING INTO SAID AIR CHAMBER, AN OUTER TUBULAR SHELL CONCENTRICALLY MOUNTED AT ITS ENDS ON THE CENTER SHAFT AND HAVING AXIALLY AND CIRCUMFERENTIALLY SPACED RADIAL OPENINGS THEREIN, INDIVIDUAL EXPANDER PLATES EXTENDING AXIALLY AND LOCATED BETWEEN THE TUBE AND OUTER SHELL FOR SUBSTANTIALLY THE LENGTH OF THE AIR CHAMBER PROVIDING CIRCUMFERENTIAL SPACES BETWEEN THE PLATES WHEN FORCED OUTWARDLY AGAINST THE INNER SURFACE OF THE OUTER SHELL, AND OUTWARDLY PROJECTING FRICTION BUTTONS ON EACH OF THE EXPANDER PLATES ALIGNED WITH THE OPENINGS IN THE OUTER SHELL FOR FRICTIONALLY ENGAGING THE INNER SURFACES OF A CORE ON THE ASSEMBLY. 